Measurement of the production cross section for Z gamma to nu nu gamma in pp collisions at sqrt(s) = 7 TeV and limits on Z Z gamma and Z gamma gamma triple gauge boson couplings

TL;DR

This paper reports a measurement of the Z gamma to nu nu gamma production cross section in proton-proton collisions at 7 TeV, confirming the Standard Model prediction and setting new limits on triple gauge boson couplings.

Contribution

First measurement of Z gamma to nu nu gamma cross section at 7 TeV, combined with previous results to set the most stringent limits on Z Z gamma and Z gamma gamma couplings.

Findings

Measured cross section: 21.1 +/- 4.2 (stat) +/- 4.3 (syst) +/- 0.5 (lum) fb.

Results agree with Standard Model predictions.

Set new limits on triple gauge boson couplings.

Abstract

A measurement of the Z gamma to nu nu-bar gamma cross section in pp collisions at sqrt(s) = 7 TeV is presented, using data corresponding to an integrated luminosity of 5.0 inverse femtobarns collected with the CMS detector. This measurement is based on the observation of events with an imbalance of transverse energy in excess of 130 GeV and a single photon in the absolute pseudorapidity range abs(eta) < 1.4 with transverse energy above 145 GeV. The Z gamma to nu nu-bar gamma production cross section is measured to be 21.1 +/- 4.2 (stat.) +/- 4.3 (syst.) +/- 0.5 (lum.) fb, which agrees with the standard model prediction of 21.9 +/- 1.1 fb. The results are combined with the CMS measurement of Z gamma production in the l+ l- gamma final state (where l is an electron or a muon) to yield the most stringent limits to date on triple gauge boson couplings: abs(h[3,Z]) < 2.7E-3, abs(h[4,Z]) < 1.3E-5 for Z Z gamma and abs(h[3,gamma]) < 2.9E-3, abs(h[4,gamma]) < 1.5E-5 for Z gamma gamma couplings.